Therefore, these products with defined 5' and 3' ends accumulate exponentially with each round of DNA amplification -- that is, for every n cycles of PCR there will be 2 -fold amplification of the specific DNA fragment.
1 By themselves, PVCâs do not present any problem.  Bigeminy, Trigeminy, Quadrigeminy, etc. - ventricular bigeminy is the occurrence of a PVC every other beat, trigeminy is every third beat, quadrigeminy every fourth beat. The main point with these types is that the PVCâs are more frequent in these circumstances. They are otherwise little different from PVCâs.
The term trisomy is used to describe the presence of three chromosomes, rather than the usual pair of chromosomes. For example, if a baby is born with three #21 chromosomes, rather than the usual pair, the baby would be said to have trisomy 21.. Trisomy 21 is also known as Down syndrome.